In wireless communication systems, transmitters typically broadcast wireless signals (such as radio frequency or “RF” signals) to one or more receivers. However, interference can occur when a receiver receives multiple wireless signals from multiple transmitters at the same time. This typically results in unrecognizable wireless signals being received by the receiver.
Conventional transmitters are often designed to operate in an interference avoidance mode, meaning the transmitters operate in a way intended to reduce or eliminate interference. For example, in time division multiple access (TDMA) systems, transmitters transmit data during different time slots. In frequency division multiple access (FDMA) systems, transmitters transmit data using different frequency bands. In code division multiple access (CDMA) systems, transmitters transmit data using spread-spectrum technology and different spreading codes. In carrier sense multiple access (CSMA) systems, a transmitter first attempts to determine whether a shared communication resource (such as a shared frequency band) is free before using that communication resource. When multiple transmitters attempt to transmit at the same time, those transmitters can implement different random backoff or waiting times before attempting to transmit again.
The goal of these and other interference avoidance techniques is to avoid producing interference at a receiver. However, interference avoidance techniques can fundamentally limit the communication capacities in wireless networks. These techniques can also limit the information processing rates in wireless sensor networks.